<p> <i>Wolbachia</i> are gram-negative, obligate, intracellular bacteria infecting a majority of insect species and filarial nematodes. In both insects and nematodes <i>Wolbachia</i> are primarily transmitted through the female germ line. <i>Wolbachia</i> carried by filarial nematodes are the cause of the neglected diseases African river blindness and lymphatic filariasis afflicting millions worldwide. In order to combat these diseases, we created a <i>Wolbachia</i>-infected Drosophila cell line that enabled high throughput screening for novel potent anti-<i> Wolbachia</i> compounds. Of the 36,231 compounds screened in house, 8 compounds dramatically reduced <i>Wolbachia</i> titer both in the cell and nematode based screen. Significantly, we discovered that the albendazole metabolite, albendazole sulfone, reduces <i>Wolbachia</i> titer in Drosophila melanogaster and the filarial nematode <i>Brugia malayi </i> perhaps by directly targeting <i>Wolbachia</i> FtsZ. Using the <i>Wolbachia</i>-infected cell line, we discovered that in addition to vertical germ line transmission, <i>Wolbachia</i> are efficiently transmitted horizontally via cell-to-cell transmission. We show that horizontal transfer is independent of cell-to-cell contact, can efficiently take place within hours, and uses both host cell phagocytic and clathrin/dynamin-dependent endocytic machinery. Modifications to our high-throughput screen in combination with genome-wide RNA interference (RNAi) identified host factors that influence <i> Wolbachia</i> titer. When these host factors were tested in <i> Drosophila melanogaster in vivo</i> we found that maintenance of <i>Wolbachia</i> titer relies on an intact host Endoplasmic Reticulum (ER) associated degradation (ERAD) system. These data, in combination with electron microscopy studies, demonstrated that <i>Wolbachia</i> is intimately associated with the host ER and suggested a previously unsuspected mechanism for the potent ability of <i>Wolbachia</i> to prevent RNA virus replication. To examine the impact of nutritional on <i>Wolbachia </i> titer, Drosophila were fed sucrose- and yeast-enriched diets. These conditions resulted in increased and decreased <i>Wolbachia</i> titer in Drosophila oogenesis, respectively, and that somatic TOR and insulin signaling mediate the response of the yeast-enriched diet on <i>Wolbachia </i>. Taken together, these studies provide initial insights into the molecular and cellular interactions between <i>Wolbachia</i> and its insect and nematode hosts.</p><p>
| Identifer | oai:union.ndltd.org:PROQUEST/oai:pqdtoai.proquest.com:10624029 |
| Date | 16 November 2017 |
| Creators | White, Pamela M. |
| Publisher | University of California, Santa Cruz |
| Source Sets | ProQuest.com |
| Language | English |
| Detected Language | English |
| Type | thesis |
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